1. Field of the Invention
My truck design pertains to skateboards, roller skates, scooters, and other skate-type devices which utilize tilting action for steering control.
2. The Prior Art
Most present trucks utilize a single axis of rotation which is an an acute angle with respect to the baseplate. The rotation of the axle yoke around the axis has both vertical and horizontal components of motion. When the rider rocks the board, one side moves up and the other side moves down. The axle rotates about the axis to accommodate the vertical change, which results in the displacement of the axle ends horizontally to produce steering action.
The prior art skate trucks feature a baseplate or soleplate which is securely fastened to the skateboard or rollerskate shoe. A wheel axle is suspended from the baseplate by rigid members. The most common truck uses a metal ball socket and a metal bolt to suspend the axle from the baseplate. These small, rigid connections experience high concentrated stresses and are prone to breakage. My truck features a T-rod and resilient pad, to bear the load from the axle to the baseplate. Neither of these parts is rigidly fixed so that breakage from sudden shock stresses are avoided. The contact surfaces between the axle yoke, T-rod, resilient pad, and baseplate are large in my design to avoid concentrated stresses. And, the resilient pad flexes to absorb shock.
The prior art skate trucks usually lack mechanical features within the truck by which the truck height and the truck steering radio can be adjusted. My truck has mechanical features by which height and steering ratio are adjustable. By providing height adjustment the skater can optimize the skateboard or roller skate riding characteristics. For small wheels, the skater can lower the truck to obtain a low stable skateboard or roller skate. Also, the skater can make the trucks taller to accomodate larger wheels.
Steering ratio adjustments change the ratio of skateboard or roller skate turning to rider tilt of the roller skate or skateboard. Typically, the standard way to adjust the skateboard steering ratio is to use a longer or shorter board. Given the same truck configuration, a short board will turn sharper than a long one. Roller skate steering ratios cannot be easily modified at all. By use of a truck with an adjustable steering ratio as disclosed in the present invention, a skateboard can be provided with different turning characteristics obtainable with a single board and a roller skate can be tuned to provide varyable steering. It is also possible with the present invention to adjust the steering ratios of each truck independently to thereby further modify the riding characteristics.
In addition to the foregoing, the prior art skate truck did not have a provision by which the trucks could be linked so as to turn together. By linking or joining the turning legs as disclosed in the present invention, mechanical synchronization between the trucks can be achieved. With synchronized turning, all four wheels are assisted in being maintained on the ground. Also, synchronized turning helps to maintain constant skateboard or roller skate tilting stiffness, even when the skater is riding on one truck only.